Add and subtract pawl action counter

ABSTRACT

A counter has a novel driving assembly including a pinion cooperating with both a number wheel and an oscillatable ratchet having a pair of pivotally mounted pawls thereon to permit selective adding and subtracting. The pinion member has two adjacent axial portions with each portion having teeth spaced about the circumference thereof. The number wheel is in meshing engagement with a first portion of the pinion and the ratchet is mounted for oscillation adjacent to the number wheel with the pawls engaging the pinion during movement thereof to urge the pinion into driving engagement with another portion of the ratchet. Biasing means is provided to prevent counterrotation of the pinion during return travel of the ratchet.

United States Patent McConnell 1 Feb. 15, 1972 [54] ADD AND SUBTRACT PAWL ACTION COUNTER [72] Inventor: Edwin J. McConnell, Windsor, Conn.

[73] Assignee: Redington Counters, Inc., Windsor, Conn.

[22] Filed: July 8, 1970 [21] Appl. No.2 53,091

[52] 11.8. CI ..235/92 C, 235/92 R, 235/92 EV [51] ..G06m 1/14,G06m 3/14 [58] Field of Search ..23S/92 C, 92 EV, 131; 340/379 [56] References Cited UNITED STATES PATENTS 2,948,471 8/1960 LaBoissiere ..235/92 EV 3,064,893 11/1962 Grinstead ..235/92 C 3,576,974 5/1971 Knox ..235/92 C Primary Examiner-Daryl W. Cook Assistant ExaminerRobert F. Gnuse Attorney-Peter L. Costas [57] ABSTRACT A counter has a novel driving assembly including a pinion cooperating with both a number wheel and an oscillatable ratchet having a pair of pivotally mounted pawls thereon to permit selective adding and subtracting. The pinion member has two adjacent axial portions with each portion having teeth spaced about the circumference thereof. The number wheel is in meshing engagement with a first portion of the pinion and r the ratchet is mounted for oscillation adjacent to the number wheel with the pawls engaging the pinion during movement thereof to urge the pinion into driving engagement with another portion of the ratchet. Biasing means is provided to prevent counterrotation of the pinion during return travel of the ratchet.

11 Claims, 13 Drawing Figures PAIENTEDFEB1 s 1972 Y 3.643.071

INVENTOR [aw/N MTowvsu.

ATTORNEY ADD AND SUBTRACT PAWL ACTION COUNTER BACKGROUND OF THE INVENTION Counters are widely employed in industry and elsewhere for recording numerical data relative to various activities; for example, they are commonly used to record the number of repetitive operations of machines such as presses, they are used on turnstiles and the like to determine the total number of people in attendance at a function or location, etc. The input to the counting mechanism may be electromechanical or purely mechanical by virtue of manual or mechanized oscillation of a suitable pivot arm. Although it is conventional to provide means in such counters whereby they can be reset by overriding the normal drive mechanism therefor, generally such reset means does not function sequentially through the entire numerical range to provide a subtracting feature. In certain instances, it is desirable to cancel one or more units regardless of the count appearing on the number wheels, and a number of devices have been proposed for this purpose. How ever, such devices have tended to be cumbersome or expensive to manufacture or to be unreliable or short lived in operation.

Directional counters known to the prior art have included those which require a spring element to supply the entire force to drive the mechanism to a neutral position, as well as to turn the counter wheels. This makes the mechanism dependent upon a relatively large spring force necessitated by the combined load. Another disadvantage of some prior art counters is that the digital indication or registering of the count on the number wheels occurs during or after the return stroke of the mechanism. This introduces a time delay which in some applications is undesirable.

In the copending application of Francis P. Knox, Ser. No. 869,996, new U.S. Pat. No. 3,576,974, filed Sept. 26, 1969 and assigned to the assignee of the present invention, there is disclosed a highly advantageous add and subtract counter in which a pinion cooperates with both the first member wheel and'an oscillatable ratchet. Biasing means urges the teeth of the pinion into engagement with the ratchet in either extreme pivoted position thereof so that the return movement of the ratchet produces rotation of the pinion in the opposite direction of rotation of the pinion in the opposite direction of rotation and the biasing means also prevents extreme pivoted position to avoid engagement with the ratchet during initial movement to either spurious actionl Devices embodying the aforesaid invention have proven quite effective, but it has been considered to register the count on the forward stroke for some. I

Accordingly, a primary objective of the present invention is to provide a novel counter for adding and subtracting which is relatively inexpensive to produce and which is highly efficient and accurate in operation.

A related object is to provide such a counter in which the actuating mechanism is relatively compact and operated by an electrical impulse to provide relatively high speed operation.

Another object is to provide a counter in which spring forces are not relied upon to drive the counter wheels and in which the timelag between the event being counted and registration thereof on the counter wheel is minimized.

SUMMARY OF THE INVENTION It has now been found that the foregoing and related objects can be readily attained in an add and subtract counter including a support carrying a rotatably'mounted pinion having two axially adjacent portions each with a multiplicity of axially extending teeth spaced about the circumference thereof. A number wheel is rotatably mounted on the support with a toothed portion thereof in meshing engagement with one of the axially adjacent toothed portions of the pinion member. Adjacent the same portion of the pinion member a ratchet member, having two pawls pivotally carried thereon, is pivotally mounted on the support for oscillation between the first and second positions and an intermediate neutral point.

The axis of oscillation is parallel to the axis of rotation of the pinion member and a pawl on the ratchet member drives the pinion member only when the ratchet member moves from the neutral point to either the first or second position.

Means is provided for selectively moving the ratchet member between the neutral point and the first position in addition to means for selectively moving the ratchet member to and from the neutral point and the second position. Biasing means operates upon the side of a tooth of the pinion to prevent counterrotation of the pinion during movement of the ratchet member from the neutral point from either pivoted position. The assembly of the biasing means, number wheel, pinion, and ratchet member cooperate to index said number wheel incrementally in a predetermined manner in response to movement of. said selective moving means.

Preferably, the biasing means operates on the side of a tooth of the pinion. The pawls carried by the ratchet member are generally L-shaped and are biased for engagement with the pinion member in the neutral position thereof and are cooperatively configured and dimensioned to provide engagement therebetween during an early portion of the movement from the neutral position to one of the pivoted positions. The pawls thereby effect rotation of the pinion and thereafter disengage from the pinionto pass thereby during the remainder of the movement of the ratchet member to the pivoted position and during return from the pivoted position to the neutral position.

In a preferred embodiment, the means for selectively moving the ratchet includes a driving member mounted for oscillation about an axis parallel to the axis of the ratchet member. The driving member and the ratchet member have complementary toothed elements to provide driving engagement therebetween. The driving member has neutral, first and second positions cooperating with the corresponding positions of the ratchet member.

Most preferably, the counter biasing means is mounted upon the driving member and is movable therewith. More specifically, the biasing means has two flat spring elements straddling the pinion member in engagement therewith, the spring elements engage tooth portions of the pinion and bias it to prevent counterrotation after rotation of the ratchet member from neutral position to first or second position and while the ratchet member is returning to the neutralposition. The nonnal spring element engagement is with a tooth on the other axially adjacent portion of the pinion member. Most preferably, the pair of flat spring elements are parts of a single generally U-shaped spring member having inwardly disposed portions normally in engagement with the toothed portions of I the pinion. The support includes a fixed element, and the driving member has an abutment element and second spring means thereon, the second spring means has two elements, one of which is positioned in closely spaced relationship on each side of both said fixed element and abutment element so that one of the spring elements bears upon one stationary element and the other spring element bears upon the abutment element when the ratchet is rotated out of the neutral position to urge the ratchet towards the neutral point. Electromechanical drive means is provided to selectively oscillate the driving member from the neutral position to either the first or second positions.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 of the drawings is a perspective view of an electromechanical counter embodying the present invention, with a portion of the frame broken away for clarity of illustration of the mechanism therein;

FIG. 2 is a front elevational view of the counter of FIG. 1;

FIG. 3A is a side elevational view of the driver invention is a the line 3-3 of FIG. 2 but to a slightly enlarged scale and showing the driver in the neutral position thereof;

FIG. 3B is a similar view showing the driver rotated in the counterclockwise direction;

FIG. 4 is a fragmentary perspective view to an enlarged scale of the pinion and adjacent counter wheel showing more clearly the cooperating teeth thereof;

FIGS. 5A5D are side elevational views along the line 5-5 of FIG. 2 showing components of the add and subtract mechanism to an enlarged scale at various stages of the add or subtract cycle;

FIGS. 6A-C are side elevational views of the ratchet and pinion assembly to an enlarged scale at several stages of the add and subtract cycle; and

FIG. 7 is an exploded view to an enlarged scale of the ratchet member and a pawl to illustrate more clearly the construction thereof.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENT Turning now in detail to the appended drawings, an electromechanical counter embodying the present invention has a support or frame, generally designated by the numeral 10, with a viewing cut out 12 in the top wall 14 thereof through which are visible for number wheels 16. The number wheels 16 are provided with circumferential teeth in a conventional manner and are rotatably mounted upon a shaft 18 which is supported between the sidewalls 20 of the frame 10. Two electromagnetic coils 22 are mounted in the bottom portion of the frame 10, and each is suitably and independently connected to an energizing source (not shown) of current which may take any of numerous forms depending upon the application for which the particular counter is intended. Clappers 24 are loosely supported at one end upon associated pedestals 26 (only one of which is visible) by seating a tongue at the upper end of the pedestal in a slot adjacent the rear edge of the clapper 24 so that one clapper is positioned to overlie each of the coils 22. The tongue 28 at the front end of each clapper 24 is received in a recess 30 provided in each of the ears 32 projecting outwardly from the sides of the driver, the latter being generally designated by the numeral 34.

The driver 34 is oscillatably mounted on a shaft 36 which is supported between the sidewalls 20, and it will be apparent that selective energization of one of the coils 22 will cause a downward movement of the associated clapper 24, which in turn will oscillate the driver 34 in either a clockwise or counterclockwise direction depending upon which coil is energized. A sear-type biasing spring 38 is mounted on the front side of the driver 34 over a boss 40 projecting therefrom; the arms of the spring 38 straddle a projecting stop block or abutment element 42 on the driver 34 and also a fixed element or shaft 44 which projects through the arcuate slot 46 in the driver 34 and is supported between the sidewalls 20 of the frame 10. As will be noted with particular reference to FIGS. 3A and 3B, the driver 34 may be oscillated to the position shown in FIG. 3B under the influence of one of the magnetic coils 22, which is of sufficient strength to override the biasing force of the spring 38. When the coil is deenergized, the sear spring 38 forces the driver 34 back to the neutral position depicted in FIG. 3A by exerting closing force upon the stop block 42 on the driver 34 and the shaft 44.

A finger 48 projects from the upper edge of the driver 34, and recesses or notches 50 are provided therein at each side of the base of the finger 48. As is best seen in FIGS. 5A-5D, a generally semicircular ratchet member, generally designated by the numeral 52, is oscillatably mounted on the shaft 18 adjacent the driver 34, and it has an arcuate or generally curvilinear edge 54 with a pair of recesses or notches 56, 56' therein. On the back side of the ratchet 52 there are provided teeth 58 (shown in dotted line in FIGS. 5A, 5B and 5C, the interior two of which mesh with the finger 48 of the driver 34. It will now be appreciated that oscillation of the driver 34 will cause the finger 48 to bear upon one of the teeth 58 of the ratchet 52, thus oscillating the ratchet 52 in the opposite direction. As the movement proceeds, the interior tooth 58 adjacent to the one acted upon by the finger 48 becomes engaged in one of the recesses 50 at its base, by which engagement the ratchet member 52 may be driven past the point at which contact with the finger 48 ceases.

Mounted on the ratchet member 52 to opposite sides of the shaft I8 are a pair of generally L-shaped pawls 65, 67 best illustrated in FIG. 7 and which are pivotably mounted at the juncture of their legs upon the pivot pins 68 of the ratchet member 52. The pawls 65, 67 have stop shoulders 7! which abut against stops 72 on the face of the ratchet member to limit pivoting thereof under the biasing action of the tension spring 70 which is connected between the ends of the legs spaced from the pinion 60. During operation of the device as will be pointed out more fully hereinafter, the pawls 65, 67 engage the narrow teeth 62 of the pinion 60.

As is best seen in FIG. 2, four pinions 60, 60' are rotatably mounted on the shaft 44 beneath the number wheels 16; the three pinions 60 serve as transfer gears between adjacent number wheels 16, whereas the fourth pinion 60 is associated with the ratchet member 52 and the first number wheel 16 and serves as a transfer gear therebetween. The construction of all pinions 60, 60' may be similar, and only pinion 60 will be discussed in detail hereinafter. As is most clearly shown in FIG. 4, the pinion 60 has two adjacent axial portions, one portion having twice the number of teeth as the other. The pinion 60 may be considered to have a number of narrow teeth 62 spaced equidistantly about the periphery of one of the axial portions (which, for the sake of description. may be designated the outer portion) and an equal number of wide teeth 64, the wide teeth 64 alternating with the narrow teeth 62, in the outer portion and extending across the inner portion and thus providing the reduced number of teeth present on the inner portion.

Referring in detail to FIGS. 5A-5D, the pinion 60 is mounted behind the driver 34 (FIGS. 5A-5D being considered a rear view) and is positioned relative to the ratchet member 52 so that the two recesses 56 of ratchet member 52 register with the inner portion of the pinion 60; in this relationship the arcuate edge 54 can pass behind the wide teeth 64 at the inner axial portion of the pinion 60. A double element cantilever spring 66 is mounted upon the rear face of the driver 34 to oscillate with it, and the elements of the spring 66 straddle the pinion 66 and operate in the plane of the inner axial portion thereof. Reference to FIG. 2 will more clearly illustrate the axial position of the pinion 60 relative to the ratchet member 52, the driver 34 and the cantilever spring 66 thereon.

FIG. 5A the novel counting mechanism of the invention in a neutral or rest position, and FIGS. 5B5D illustrate the mechanism at various stages during the registration ofa count. It will be noted that in FIG. 5A the portion of the arcuate edge 54 of the ratchet member between the recesses 56, 56' is positioned behind two of the adjacent wide teeth 64", 64" of the pinion 60 on the inner axial portion having the reduced number of teeth. Also both elements of the cantilever spring 66 are in contact with the pinion 66, specifically, tips 660 and 66b abut the sides of the wide teeth 66 of the inner portion of the pinion 60.

As clockwise movement of the driver 34 initiated by one of the coils 22 (not shown in FIGS. 5), the finger 48 bears upon one of the teeth 58 of the ratchet member 52 and urges the ratchet member 52 in a counterclockwise direction. This stage of operation is illustrated in FIG. 5B, which also shows the left hand element of the spring 66 bearing upon one face of one of the wide teeth 64' at the inner axial portion of the pinion 60. The influence of the spring 66 on the tooth 64' biases the next radially spaced wide tooth 64" to avoid any tendency for engagement in the recess 56, which would give a spurious indication.

Upon rotation of ratchet member 52 to the clockwise position shown in FIG. 5D, the pawl 65 is positioned for driving engagement with pinion 60 as shown in FIG. 6A. FIGS. 5B and 6A show the elements at the same instant in the operational sequence. Upon still further rotation of ratchet member 52 the pawl 65 abuts a narrow tooth 62'.

As clockwise movement of the driver 34 continues, as is shown in FIG. 5C, the wide interior tooth 58 of the ratchet member 52 adjacent the tooth against which the finer 48 was bearing enters the recess 50 on the left-hand side of the finger 48, and is engaged by the shoulder of the driver member 34 defining that recess. This engagement permits the driver 34 to urge the ratchet member 52 further in a counterclockwise direction. As shown in FIG. 68, at this point in the operational cycle the pawl 65 no longer engages the pinion 60.

During the last phase of clockwise travel of the driver 34, the ratchet member 52 has passed far enough to permit recess 56 thereof to engage tooth 64" of pinion 60 as shown in FIGS. 5C, 68, and 6C. The pinion is driven in this manner to the position shown in FIG. 5D where an element of spring 66 biases the pinion 60 further clockwise where upon spring end 66a abuts the side of the tooth 64' in the general manner shown in FIG. 5A. The biasing spring force which prevents undesired reverse rotation is greater in the position shown in FIG. 5D because of the displacement of the driver 34 which carries the spring 66. The teeth 62 on the pinion 60 are suitably interengaged with complementary teeth 63 on the adjacent number wheel 16 so that rotation of the pinion 60 in turn causes rotation of the associated number wheel 16 a sufficient distance to expose a sequential digit in the viewing aperture 12, thus registering a count.

in the position shown in FIG. 5D, the relationship of the several parts is shown at a point after the clockwise movement of the driver 34 has reached its extreme, and the biasing spring 38 becomes effective to move the driver 34 in a counterclockwise direction back to its neutral position. The force of the biasing spring 38 then urges the driver 34 to its neutral position which, in turn, oscillates the ratchet member 52 in a clockwise direction by interengagement of the finger 48 of the driver with the teeth 58 of the ratchet 52. The pawl 65 that urged the pinion 64 to rotate then is pivotally deflected by a pinion tooth despite the bias of spring 70. This deflection allows return of the driver to its neutral position without interference by the pawl 65.

When it is desired to rotate the pinion and associated number wheel in the opposite direction to cancel a count recorded as previously described, the operating sequence varies primarily in that the driver 34 moves counterclockwise initially. The general operation of he cantilever spring 66, driver 34, ratchet member 52, and pinion 60 is the same.

Although the drawings illustrate preferred embodiments of the invention, it should be appreciated that considerable deviation from the mechanism and elements illustrated therein is possible without departing from the concept thereof. Thus for example, it is possible to employ a pinion wherein the number of teeth in one of the adjacent axial portions is related to the number in the other portion by a factor other than 2, although this will normally entail suitable redesign of the cooperating number wheel and particularly the toothed portion thereof. It is also possible to utilize biasing means operating on the pinion other than the double element cantilever type spring illustrated, and such biasing means may be mounted on a part of the device other than the driving member.

The described construction is desirable because it minimizes the load upon the sear spring 38. The time delay is so small that the digital indication is produced almost immediately upon actuation of the driver in its direction of operation. Spurious indications which might result from frictional drag of the pawls 65, 67 on the pinion 60 are avoided by the biasing action of the spring 66. Accordingly, it can be seen that the present invention provides a novel counter for selectively adding and subtracting. The counter is relatively simple and inexpensive to produce, while nevertheless being highly efiicient and accurate in operation. The counter does not rely on spring forces to drive the counter wheels and registers the count without significant time lag after the event being counted. The concept of the invention is especially applicable in the production of compact electromagnetic counters which offer relatively trouble-free operation.

lclaim:

1. in an add and subtract counter, the combination comprising:

a. a support;

b. a pinion rotatably mounted on said support and having two axially adjacent portions each with a multiplicity of axially extending teeth spaced about the circumference thereof, one of said portions having a greater number of teeth than the other of said portions;

c. a number wheel member rotatably mounted on said support and having a toothed portion in meshing engagement with the teeth of said one axially adjacent portion of said pinion;

d. an arcuate ratchet member pivotally mounted upon said support and having two pawls pivotally carried thereon on opposite sides of the pivot thereof and engageable with the teeth of said one axially adjacent portion of said pinion, said ratchet member being oscillatable between first and second position and through an intermediate neutral position, the axis of oscillation being parallel to the axis of rotation of said pinion, said ratchet member pawls having opposed ends biased toward engagement with said pinion in said neutral position of said ratchet member and driving said pinion only when moved from said neutral position to said first position or from said neutral point to said second position;

e. means for selectively moving said ratchet member between said neutral point and said first position and between said neutral point and said second position; and

. biasing means operative upon a side of a tooth of said pinion during movement to the neutral position from either pivoted position to prevent counterrotation whereby said biasing means, pinion and ratchet member cooperate to index said number wheel incrementally in a predetermined manner during movement of said ratchet member from said neutral position to one of the pivoted positions thereof in response to movement of said selective moving means.

2. The counter of claim 1 wherein said pawls are generally L-shaped and wherein said pawls and the teeth of said pinion are cooperatively configured and dimensioned to provide engagement therebetween during an early portion of the movement from the neutral position to one of the pivoted positions of said ratchet member to effect rotation of said pinion and thereafter disengaging therefrom to pass thereby during the remainder of the movement of the ratchet member to the pivoted position and during return from the pivoted position to the neutral position.

3. The counter of claim 1 wherein said means for selectively moving said ratchet member includes a driving member mounted for oscillation about an axis parallel to said axis of oscillation of said ratchet member and wherein complementary toothed elements are provided on said driving member and ratchet member to provide driving interengagement therebetween, said driving member having neutral, first and second positions cooperating with the corresponding positions of said ratchet member.

4. The counter of claim 3 wherein said biasing means is mounted on said driving member and is moveable therewith.

5. The counter of claim 4 wherein said biasing means includes a pair of flat spring elements straddling said pinion and normally in engagement therewith, Said spring elements engaging tooth portions of said pinion and biasing said pinion to prevent counterrotation after rotation of said ratchet member from said neutral position to one of said first and second positions and while said ratchet member is returning therefrom to said neutral position.

6. The counter of claim 5 wherein said spring elements are normally engaged with teeth on said other axially adjacent portion of said pinion.

7. The counter of claim 6 wherein said pair of flat spring elements are the legs of a single generally U-shaped spring member with inwardly disposed free ends portions, said end portions being normally in engagement with teeth on said other portion of said pinion.

8. The counter of claim wherein said support includes a fixed element, and wherein said driving member has an abutment element and second spring means thereon, said second spring means having an element positioned on each side of both said fixed element and said abutment element so that one of said spring elements bears upon said stationary element and the other bears upon said abutment element when said ratchet member is rotated away from said neutral point to urge said driving member back towards said neutral position.

9. The counter of claim 3 wherein said counter includes electromechanical drive means to selectively oscillate said lO jacent portion of said pinion. 

1. In an add and subtract counter, the combination comprising: a. a support; b. a pinion rotatably mounted on said support and having two axially adjacent portions each with a multiplicity of axially extending teeth spaced about the circumference thereof, one of said portions having a greater number of teeth than the other of said portions; c. a number wheel member rotatably mounted on said support and having a toothed portion in meshing engagement with the teeth of said one axially adjacent portion of said pinion; d. an arcuate ratchet member pivotally mounted upon said support and having two pawls pivotally carried thereon on opposite sides of the pivot thereof and engageable with the teeth of said one axially adjacent portion of said pinion, said ratchet member being oscillatable between first and second position and through an intermediate neutral position, the axis of oscillation being parallel to the axis of rotation of said pinion, said ratchet member pawls having opposed ends biased toward engagement with said pinion in said neutral position of said ratchet member and driving said pinion only when moved from said neutral position to said first position or from said neutral point to said second position; e. means for selectively moving said ratchet member between said neutral point and said first position and between said neutral point and said second position; and f. biasing means operative upon a side of a tooth of said pinion during movement to the neutral position from either pivoted position to prevent counterrotation whereby said biasing means, pinion and ratchet member cooperate to index said number wheel incrementally in a predetermined manner during movement of said ratchet member from said neutral position to one of the pivoted positions thereof in response to movement of said selective moving means.
 2. The counter of claim 1 wherein said pAwls are generally L-shaped and wherein said pawls and the teeth of said pinion are cooperatively configured and dimensioned to provide engagement therebetween during an early portion of the movement from the neutral position to one of the pivoted positions of said ratchet member to effect rotation of said pinion and thereafter disengaging therefrom to pass thereby during the remainder of the movement of the ratchet member to the pivoted position and during return from the pivoted position to the neutral position.
 3. The counter of claim 1 wherein said means for selectively moving said ratchet member includes a driving member mounted for oscillation about an axis parallel to said axis of oscillation of said ratchet member and wherein complementary toothed elements are provided on said driving member and ratchet member to provide driving interengagement therebetween, said driving member having neutral, first and second positions cooperating with the corresponding positions of said ratchet member.
 4. The counter of claim 3 wherein said biasing means is mounted on said driving member and is moveable therewith.
 5. The counter of claim 4 wherein said biasing means includes a pair of flat spring elements straddling said pinion and normally in engagement therewith, said spring elements engaging tooth portions of said pinion and biasing said pinion to prevent counterrotation after rotation of said ratchet member from said neutral position to one of said first and second positions and while said ratchet member is returning therefrom to said neutral position.
 6. The counter of claim 5 wherein said spring elements are normally engaged with teeth on said other axially adjacent portion of said pinion.
 7. The counter of claim 6 wherein said pair of flat spring elements are the legs of a single generally U-shaped spring member with inwardly disposed free ends portions, said end portions being normally in engagement with teeth on said other portion of said pinion.
 8. The counter of claim 5 wherein said support includes a fixed element, and wherein said driving member has an abutment element and second spring means thereon, said second spring means having an element positioned on each side of both said fixed element and said abutment element so that one of said spring elements bears upon said stationary element and the other bears upon said abutment element when said ratchet member is rotated away from said neutral point to urge said driving member back towards said neutral position.
 9. The counter of claim 3 wherein said counter includes electromechanical drive means to selectively oscillate said driving member from said neutral position to said first and second positions.
 10. The counter of claim 9 wherein said one of said two axially adjacent portions of said pinion has twice the number of teeth in said other portion and wherein said ratchet member has an arcuate surface with a plurality of notches therein receiving teeth of said other portion.
 11. The counter of claim 10 wherein said biasing means operates against the side of a tooth of said other axially adjacent portion of said pinion. 